There can't be a practical reason for believing something that is not true.

Democracy is the process by which people choose the man who'll get the blame.

The main thing needed to make men happy is intelligence.

At the age of eleven, I began Euclid, with my brother as my tutor. ... I had not imagined that there was anything so delicious in the world. After I had learned the fifth proposition, my brother told me that it was generally considered difficult, but I had found no difficulty whatsoever. This was the first time it had dawned on me that I might have some intelligence.

A man is rational in proportion as his intelligence informs and controls his desires.

Our use of the phrase 'The Dark Ages' to cover the period from 600 to 1000 marks our undue concentration on Western Europe. [...] From India to Spain, the brilliant civilisation of Islam flourished. What was lost to Christendom at this time was not lost to civilisation, but quite the contrary. [...] To us it seems that West-European civilisation is civilisation, but this is a narrow view.

Truth is for the gods; from our human point of view, it is an ideal, towards which we can approximate, but which we cannot hope to reach.